The geometrical efficiency equation for a proton recoil telescope exposed to a monoenergetic point neutron source is solved by a power series expansion that permits simple and accurate reduction of raw telescope data to absolute neutron fluxes or source strengths. Two parameters are allotted for description of source anisotropy and three parameters are allotted for description of hydrogen scattering anisotropy in the center-of-mass system. The relativistic transformation of the hydrogen differential scattering cross section from center-of-mass to laboratory system is used.